In the diagram cell electrolysis of brine, chlorine gas is generated at the anode and an aqueous solution containing about 9 to 11 percent by weight sodium hydroxide and from about 12 to 15 percent by weight sodium chloride, along with trace amounts of sodium chlorate, is typically produced at the cathode. The cathode cell liquor is usually concentrated, by evaporation, to about 50 percent by weight sodium hydroxide, and the sodium chloride, only about 1 percent by weight of which is soluble in 50 percent caustic, is recovered and recycled to the brine feed.
Applicants have devised an alternative use for cathode cell liquor wherein the cell liquor is utilized as a starting material for the continuous production of aqueous hypochlorous acid which is known to have excellent bleaching properties.